Capillary-tube-system micrometer.



W. REOHNIOWSKI. OAPILLARY TUBE SYSTEM MIOROMETER.

APPLICATION FILED MAY 7, 1914.

Patented Mar. 30, 1915.

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' Application filed may 7, 191A. Serialjto. 836,972.

and a residentof St. Petersburg, Russia,

have invented certain new'and useful Improvements in Capillary-Tube ystem Micrometers, of which the following is a specitication,

Tn existing devices for measuring variations in length of a body, the amount of variation is magnified-many times, to make such measuring possible by means of a system of levers with arms of unequal length.

However, such devices ofi'er various dilfL culties and besides mistakes in measuring may easily be made.

The present invention relates to a simplified manner of measuring length variations, by means of a piston moving in a cylinder filled with liquid and actuated by contact with the object to be measured, the cylinder being provided with narrow tubes, on which may be read ofi the variations in the level of the. liquid caused by the axial displacement of the piston, thus magnifying this displacement, which corresponds to the variation in length of said object.

Tn the accompanying drawing, Figure l is a side view of the device; Fig. 2 a front view of the same and Fig. 3 a vertical section of the cylinder.

As seen on the drawing, the device consists of a cylinder 1 with a movable piston 2, to which is connected a pin with a nut 3.

On each side of the piston 2 the cylinder is filled with a suitable liquid, for instance, mercury, and from each chamber formed in the cylinder by the movable piston, a narrow tube 5 projects, extending along a scale 6. Each tube 5 is provided at its upper end with a cook or plug 13 for the purpose of closing the tubes.

As the area of the piston represents a multiple of the cross-section of the tubes, every displacement of the piston will result in a movement of the liquid in the tubes, the extent of which represents a multiple of the movement of the piston. The tubes may be provided underneath with a joint 14: or an elastic guttapercha sleeve in order to insure as far as possible their vertical position in case the rod 10 or object to be tested should not be exactly in vertical position. The whole apparatus is fastened to a fixed rod 7, which, at its upper end may be secured, by means of a clamp 8 and set- Speciflcation of Letters JPatent.

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force acting on such a rod at a given'moment, the'elongation'in a certain length L of the object, is measured in the following way :lBefore the force acts, the clamps 8 and 11 are tightly secured to the object 10 at a distance L from each other by means of set-screws 9 and 12. Thereafter, by the help of'an adjusting nut 3 the liquid is brought to one and the same level in both tubes 5. As it is difficult to perform this by means of a single adjusting nut on account of the great difierence between the areas of the large piston surface and of thesmall crosssection of the tubes 5, an auxiliary adjusting device 4 of known construction, such as adjustin screws, plungers or membranes is provi ed in cylinder 1 on either side of the piston, the area of which is not differing so much in respect to the orifice of the tubes. The auxiliary adjusting devices 4, here represented by two screws, are screwed in or out of the respective chambers formed above and below the piston 2. As a consequence the liquid will rise or fall in the corresponding pipes 5, and the levels may thus be equalized in these pipes. When the object under examination is subjected to a strain, then the change of the level of the liquid and also the extent of the elongation may be read ofl' on the scale. During the measuring both tubes 5 must naturally be in communication with the atmosphere.

While the piston is moving owing to the change in length of the body under examination, the liquid in both narrow tubes is moving in opposite directions, 2'. 6. while the level of the liquid in one of the tubes rises, the level in the other tube is sinking correspondingly. In this way is attained the essential advantage of elimination of an error in the reading, resulting from the influence of the change in temperature during the measuring), as this influence is manifesting 0th sides of the piston; because,

- case a prismatic rod 10, or to determine the with equal volumes of liquid on both sides of the piston, the level of the liquid 1n both narrow tubes rises and falls in equal degrees through change of temperature.

The distance between the two levels of the liquid comprises a 2021. multiple of the displacement 0 the lston where m IS the ratio of the areaof t e plston to'the crosssection of the tubes.

With the help of a table it is then possible with a given ratio between the alteration of the elongation and the length L of the object under examination to determine the extent of the operating power P on the ground of the formula of clamps for engaging the object to be ject to be treated, one of sai treated, one of i s y connected with the ylinder and the other with the piston and a fine-adjustin device between said slidable clamp and sai' piston.

2. instrument for measuring variations m length of a body comprising a c linder a piston normally ositioned centra y in said cylinder, thus orming a chamber at each end, capillary tubes one communicating with one end of each chamber and running parallel outside of said cylinder, a common scale for said tubes, said chambers and part of said tubes being filled with liquid, a pair of clamps for en aging the obclamps being rigidly connected with the cylinder and the other with the piston fine-adjusting device between said slldable clamp and said piston, and an auxiliary adjusting device in said cylinder, comprising a capacity varying member in each chamber, whereby the level of the liquid may be raised or lowered in each tube.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

WAZLAW REOHNIOWSKI.

Witnesses:

H. A. LOVIAGUDIE, A. N. Tsonnmmrr'. 

